I put some thought into it myself, haha:
TAR 20 Leg 6 - The Apple side of the Detour where they had to look for a marked apple. It seemed a lot like the tomato challenge from TAR 10, but only like 2 teams did this challenge and they were both racing for last.
TAR 21 Leg 9 - The Switchback Roadblock!
TAR 22 Leg 12 - The Globe challenge